The present invention relates to the field of catheters, and more particularly to a catheter having a flange to control the depth of insertion of the catheter.
Many catheters are known which are used to inject fluid to, or extract fluid from, an organ of a human being or similar animate object. One problem with such known catheters is that it is very difficult to control the insertion depth of the catheter into the organ. If the catheter is under-inserted, the fluid will not be provided to or extracted from the organ at the location desired. This can cause great difficulties when the catheter is used in surgery. The patient will not receive sufficient fluids from the catheter resulting in a failed operation. On the other hand, if the catheter is over-inserted the catheter may damage the organ walls in addition to providing fluid to or extracting fluid from the wrong location in the organ. Thus, it is necessary to insert a catheter to the correct depth within the organ. The present invention proposes a solution to this problem.
While the present invention is described in terms of a catheter to be used in retrograde cardioplegia solution administration in the coronary sinus during heart surgery, it is to be understood that the subject catheter may be used in any field of catheter application. Those having ordinary skill in this field will recognize the advantages of the claimed structure, and its application to a wide variety of catheter uses.
The problem of controlling the insertion depth of a catheter is particularly significant during open heart surgery. During such surgery, the patient's heart is stopped and the functions thereof are taken over by a heart-lung machine. In stopping the heart, care must be taken to prevent the heart muscle from continuing to beat without blood being supplied thereto. If the heart continues to beat without a proper blood supply, mycardial infarction (heart muscle necrosis) will result. In situations of ongoing ischemia, it is especially important to preserve mycardium.
To quickly and safely stop the patient's heart, it is known to provide a cardioplegia solution to the heart muscle which quickly arrests the muscle, thus preventing the heart from beating with an inadequate supply of blood. One way to provide such cardioplegia solution to the heart muscle is to inject it into the arteries leading to the heart muscle. Such antegrade introduction of the cardioplegia solution may be very difficult, however, due to aortic insufficiency or severe coronary arterial obstructions. Such insufficiency and obstructions prevent the adequate distribution of cardioplegia solution through the routine antegrade approach. Since many patients require heart surgery because of aortic insufficiency and/or severe coronary arterial obstruction, it is often difficult to provide the cardioplegia solution through the normal antegrade approach.
Another method of providing the cardioplegia solution to the heart muscle is called retrograde coronary sinus administration. In this approach, the cardioplegia solution is inserted into the veins leading from the heart muscle and then caused to flow backward (retrograde) into the heart muscle itself. Such a solution is attractive since the coronary veins of the heart muscle do not develop blockages. During retrograde coronary sinus cardioplegia solution administration, a catheter is inserted through the right atrium of the heart into the coronary sinus. Once in position, cardioplegia solution is caused to flow from the catheter into the coronary sinus, and from there back into the vein bed of the heart muscle itself. Such retrograde coronary sinus cardioplegia solution administration is a relatively new procedure with many advantages over the known antegrade approach.
A problem with the retrograde approach is the requirement to fully block the coronary sinus after the catheter has been inserted in order to prevent the cardioplegia solution from flowing backward from the coronary sinus into the right atrium. Another problem with the retrograde approach is controlling the insertion depth of the catheter into the coronary sinus. The right atrium and the coronary sinus are made of particularly fragile tissues which easily tear when probed with a catheter. If the catheter insertion depth is not properly controlled, extensive damage to the right atrium and/or the coronary sinus will result. Control of the insertion depth of the catheter is also important to provide the cardioplegia solution to the correct location in the coronary sinus and to prevent it from flowing back into the right atrium.
In France, retrograde coronary sinus administration of cardioplegia solution is being practiced but with a catheter that requires insertion under direct visual observation. Thus, the French approach is to cut open the right atrium and drain it, and then visually insert the catheter into the coronary sinus. Cutting open the right atrium requires a longer opertive time and adds to the risk of the surgery.
Thus, there is a need for a catheter whose insertion depth can be precisely controlled. For use in retrograde coronary sinus cardioplegia solution administration, such a catheter should include a device for blocking the coronary sinus to prevent the cardioplegia solution from flowing backward into the atrium. Such a catheter should also include a very soft tip to prevent tearing the walls of the right atrium and/or the coronary sinus. Such a catheter should also be capable of being inserted blindly without direct visualization so that it can be inserted through a purse string opening in the right atrium so that the right atrium does not have to be cut open.